I used to shoot 3" 12 gauge BB hevi shot, but it got expensive and I do a lot of goose hunting for snows down here. I bought a NEF in 10 gauge and now shoot 3.5" 10 gauge steel T shot. If I had a 3.5" 12, I'd shoot T in it. I just wanted a 10, never owned one, figured it was time. I may get an ultimag or BPS 12 3.5" in the future to play with, or a BPS 10. Really, the single shot is not a big hindrance. If they're set and landing, I have time to reload before their out of range. If they're way up there, another shot is USUALLY a waste, though I have doubled up with hevishot in my Mossberg before. But, the single shot is kinda fun, simple, rugged, and I don't worry about it out in the salt marsh since it was pretty cheap.
Lately, I've been thinkin' of trying some BB in fast steel loads. One advantage to 12 gauge 3.5" is that you can get fast steel loads in 'em, they run higher pressures than 10 gauge. 3" fast steel BB might work pretty well. I shot a rosses goose (looks a bit like a small snow) 45 yards high, over 40 anyway, this year with number 3 fast steel. It was a prayer shot, I was loaded for ducks. To my surprise, he folded and fell. I looked all over his head and neck and couldn't find a hit, just peppered his breast. I was impressed with that. I just stared using fast steel, specifically 2 3/4" Winchester Expert 1550 fps on ducks several years ago. They are VERY effective on ducks, much more effective than the old steel. I'm really impressed with the stuff at this point.
I hope your hunt goes better than ours this season. I hunt public, otherwise, and the walking and everything is a bigger pain. My buddy and I usually get one guided hunt every season. We froze our butts off for 3 birds. Last year was much better.
